Ecomorphology of the Tongues of Australian Megachiroptera (Chiroptera: Pteropodidae)

Abstract

The tongues of six species of Australian megachiropterans were studied macroscopically and microscopically to observe whether there were any morphological characteristics correlating with their foraging and feeding behaviour. Tongues varied from being extensible and brush-like (with long hair-like papillae) in Syconycteris australis, to club-like (with very few types of papillae) in Nyctimene robinsoni, to long-pointed (possessing several types of surface papillae) in the Pteropus species. The morphology of the tongue of S. australis and the Pteropus species was similar to that of nectar-feeding birds, marsupials and other mammals. N. robinsoni possessed a tongue highly structured for processing the fruit on which it feeds, whilst the tongue of the S. australis and P. scapulatus was highly structured for a diet predominantly made up of nectar. Although the surface papillae were similar among P. poliocephalus, P. alecto and P. conspicillatus, the shape of the tongue varied considerably, suggesting that there may be subtle differences between individual feeding strategies. The morphology of the tongues in this study, combined with field observations, suggest that many megachiropterans are able to consume different food types when their preferred food source is unavailable. In addition, the structure of tongue and its papillae support the role of megachiropterans in both pollination and seed dispersal.